It is widely accepted that exercising at the right intensity, generally measured by heart rate, is one of the keys to achieving a desired fitness goal. Some heart rate zones are more effective for burning fat, while others are better for improving stamina. A wide variety of monitors are known and commercially available for measuring heart rate while exercising. See, for example, U.S. Pat. Nos. 5,365,934 issued to Leon et al., 5,738,104 issued to Lo et al., 5,807,267 issued to Brayers et al., and 6,163,718 issued to Fabrizio., the disclosures of which are hereby incorporated by reference.
It is a common practice to equip stationary exercise equipment with a heart rate monitor and associated display so that a user is apprised of their heart rate during a workout session and can modify their workout regimen (e.g., change workload by changing resistance or speed) to achieve a desired heart rate during various stages of the workout session. See, for example, U.S. Pat. Nos. 5,527,239 issued to Abbondanza, 5,598,849 issued to Browne, 6,165,129 issued to Bates, 6,512,947 issued to Bartholome, 6,554,776 issued to Snow et al., 6,584,344 issued to Hannula, and 6,626,800 issued to Casler, the disclosures of which are hereby incorporated by reference.
It is also known to equip stationary exercise equipment with a control system capable of monitoring the heart rate of a user and automatically adjusting certain parameters on the exercise equipment during a workout session, based upon a preselected and/or predetermined target, for purposes of modifying the workout regimen to achieve and/or maintain a desired heart rate during various stages of the workout session. See, for example, U.S. Pat. Nos. 5,462,504 issued to Trulaske et al., 5,527,239 issued to Abbondanza, 5,618,245 issued to Trulaske et al., 5,803,870 issued to Buhler, 5,853,181 issued to Maruo et al., 6,033,344 issued to Trulaske et al., 6,304,774 issued to Gorman, 6,450,922 issued to Henderson et al., 6,605,044 issued to Bimbaum, 6,648,798 issued to Yoo, the disclosures of which are hereby incorporated by reference.
One type of stationary cardiovascular exercise equipment which has become extremely popular based predominantly upon its low-impact and natural motion is the elliptical exercise machine. A wide variety of elliptical exercise machines have been developed. Briefly, elliptical exercise machines include foot supports supported upon foot links with the foot links pivotally connected at a first end through a linkage system to a drive shaft for travel along a defined closed loop path (e.g., circular, elliptical, oval, etc.) and connected at the other end for reciprocating motion along a defined path as the first end travels along the closed loop path. This combination of looping and reciprocating paths of travel at opposite ends of the foot links impart an “elliptical” type motion to the foot supports attached to the foot links.
Such elliptical exercise machines permit a user to adjust the location of various connection and/or contact points on the machine to vary the incline of the elliptical motion of the foot supports at the start of a workout session and to exercise at different speeds during the workout session. These features significantly enhance the value of the machine by permitting a user to select the desired level of difficulty for a workout session by adjusting the incline of the elliptical motion of the foot supports, and to exercise at varying speeds during the workout session. However, these machines do not alter the path of travel of the foot supports during a workout session based upon real-time variables.
Accordingly, a need exists for elliptical exercise machines which permit a user to exercise at varying speeds and automatically alters the path of travel of the foot supports during a workout session dependant upon the heart rate of the user.